I have a 6 month old CM tev026 open loop need some low temp lockout advise. communicating thermostat w/vflow well water pressure reduced to 30 psi 3psi pressure drop 52 degree incoming water 48.4 out (delta set at 4 on stat) lt1 temps below 30 degree lockout threshold constantly lt 2 temp 89 leaving air 107 degrees incoming air 65 measured at the intake plenum unit set to lowest cfm 600 comp discharge 195.4 I recently upgraded my cpu to the latest software, and replaced my lt1 thermistor....still having problems I have been surviving by lifting the thermistor slightly to fool the system. This is my first post but have read many thx.
I have been staying away from CM since they started sizing pumps for me. How do they know what I put in the ground or pond (sorry Doc) for loops? The refrigeration chassis are mostly made by one manufacturer. That is why they all look alike. What happens is different control systems, blowers, panel material and paint color. They all want 3 GPM per ton flow R-22 or R-410A. I am not sure how good an idea it is to randomly up grade electronic hard ware for a chassis built way back when. Six months can be a long time for CPU upgrades. I do not think I have ever seen a thermister that was not based on 10K. Why the upgrade? Who's idea was it. Where are the old parts? Has the antifreeze jumper (J-1) been clipped? On the new board or the old board? Has either thermistor been tested to a know good digital thermostat for resistance? Has either thermistor been check with an ohm meter of good reputation and quality? I could not take a shower with 30 PSI water. I have been hugging trees since John Shuttleworth started the Mother Earth News. That is not enough water to get the prell out of what is left of my gray hair. I think you need help. Hello and welcome BTW. Mark
I have a dedicated well vfd @30 gpm. I am using a pressure reducing valve per iom {same results with 60psi or 30, flow not psi important in geo) thermistors checked out with fluke. the cpu flash is current software which addresses lt1 lockout time/temp algorithms. One thing I don't like is if I run the unit in manual mode I can open the v flow valve to 100% which gives me a delta water temp of 2 or so and the lt1 stays in range. With normal operation the cpu min delta setting is 4 and valve position is around 70% j1 not clipped open loop do they still sell Prell?
Kupe Do NOT clip anything. 30F degree freeze protection is correct for open loop. CM recommends 30psi for Vflow open loop mod valves. Are measurements taken at full capacity with HWG off? They should be. Is your TEV026 in an unconditioned space? Airside deltaT (42F) is very high unless aux heat is also on. IOM says it should be between 23-29F deltaT and 840-950cfm in 2nd stage heating.
I slowed the cfm way down which raised the out air out so high in attempt to raise my lt1 temp it helps a bit. if I bump it up to 850 the out put air settles around 95out with 65 incoming which is fine but it will lockout in minutes. the unit is in a 65 degree basement btw I have confirmed second stage is working.
You need to be careful when defeated freeze protect sensor. Where is the dealer who put this in. I know you said you have had the unit for 6 months, but how old is it? (ser. number). How are you checking PSI drop?
Joe we emailed back and forth a little I did not want to take advantage of your time. I bought the unit online and contracted the installation including a new well , I am measuring pressure drop at the Schrader ports, stage two the unit is a 2013. Per your advice Joe I now have the latest software, my online dealer has been more than helpful. I am trying to rule out everything before checking the refrigerant. My closest dealer would be around 1.5 hrs one way, that was my incentive to handle this myself. Thanks
Ok. What we need to establish is whether you have adequate gpm with a discharge side measurement of of actual flow. Also should find out age. Since 2 tons is less common you could have a unit made before the pc board update. Can you get a pic of your pc board?
Happy day! my refrigerant was a bit low. could not find any leak...good news too. I turned up my cfm to max and increased my water delta temp as a test and no lt1 lockouts. Thank all for the advice
I love good news. Low refrigerant on a new unit does not always mean a leak. Having toured a couple of manufacturing plants it is a wonderment to me that any of this stuff runs out of the box. Cars, (mobile) are worse. I know if there is a leak the machine will let you know. I have a W2W climate master with an intermittent TXV that I can never catch misbehaving enough to call for a replacement valve. I have stopped messing with the charge. There are some good stop leak products for refrigeration system out now, I would check with CM before adding to a new unit. Love the good news, Mark
I have had a CM shipped light in 410. Best procedure should be to weigh it out and weigh it back in. Also recently recieved a service bulletin about Copeland compressors. There is an additive in some that was gumming up TXV's.
